can i use old car battries?

[vm1990]

So im new here (duh)
if i go to a scrap yard and buy a few old Lead acid car batteries would it be safe to use them with the cheap ebay PWM charge controllers, im not that fussed about life span and such its more just for a plaything until i get a MPPT charge controller and some proper leisure batteries

also is there a way to get 2 different AH batteries to hook up together to 24v? or is it just generally a bad idea

got to learn some how, so far built my own solar panels and bought 3 damaged 255watt ones off ebay (im poor as hell) but its all a bit of fun for now

[inetdog]

So im new here (duh)
if i go to a scrap yard and buy a few old Lead acid car batteries would it be safe to use them with the cheap ebay PWM charge controllers, im not that fussed about life span and such its more just for a plaything until i get a MPPT charge controller and some proper leisure batteries

also is there a way to get 2 different AH batteries to hook up together to 24v? or is it just generally a bad idea

got to learn some how, so far built my own solar panels and bought 3 damaged 255watt ones off ebay (im poor as hell) but its all a bit of fun for now

Welcome!
It is safe to carefully use old lead acid batteries, but they will not be good for anything except experimenting and very very short term projects.
They are usually sulfated from sitting uncharged for too long even if they are not mechanically damaged.
There is no safe way to put two different capacity 12V batteries in series to get 24V.

[Raul]

Hello vm 1990 , I use truck batteries from scrappy for outside garder/drive lighting on my second year now. Get a multimetre with you and pick some with 12v+ . My local accepts lead scraps from roofing works in exchange of batteries. Once you done with them return for scrap. Lead prices are up

[Mike90250]

also is there a way to get 2 different AH batteries to hook up together to 24v? or is it just generally a bad idea

Very bad idea, one will overcharge, and other will be undercharged

[vm1990]

thought as much, i did buy a sealed battery that had been used on an old solar array and had been sitting for about 6 months (wasnt dirt cheap but worth taking a risk on but id say its only about 80% at best wont sit above 12.5v)
the idea is to get to a point where a couple times a week i can run a 1KW bitcoin miner off the system (voltage isnt to big an issue as i have enough gear to step it down to 12v and 5v so dont need high end inverters)

but its fun got alsorts running off the panels at the moment
30v stepped down to 5v (feels very wasteful) but get a few amps which i channel into a USB hub which then lets me charge some of those cheap li-pol portable USB batteries, which i can use to charge mobile phones and gadgets.

iv got the 12v 45ah battery on a home solar panel 3x6 cells turned into 3 12v small panels and then linked together. was my first project, couldnt find a good way to mount them so tried the laminate from a DIY store (stuff you use to laminate cupboards and stuff) which turned out quite nice (got bubbles and a few crack but holds everything together very nice and doesn't affect them to much)

i know i should invest in more expensive batteries and stuff but no point buying expensive stuff when i can break and learn from the cheap stuff first XD

[vm1990]

Very bad idea, one will overcharge, and other will be undercharged

thanks i did read a few people do it but in my mind all batteries on a system like to be the same, if one gets weakened all the others will pick on it (its the easiest way i can think of it)

[Sunking]

Never mind, not going to waste my time on stupid stuff. Better to let you waste your money and time so you learn something.

[vm1990]

Never mind, not going to waste my time on stupid stuff. Better to let you waste your money and time so you learn something.

Yep you have time to waste with a pointless reply. I'm asking for help if you don't want to give help or advice then don't, I really don't mind and it's not no problem for someone not to give advice

[SunEagle]

Yep you have time to waste with a pointless reply. I'm asking for help if you don't want to give help or advice then don't, I really don't mind and it's not no problem for someone not to give advice

I have one question. If you are "poor as hell" why are you wasting your money on batteries and solar power?

Unfortunately you will never save money generating your own power compared to purchasing it from a POCO.

[vm1990]

I have one question. If you are "poor as hell" why are you wasting your money on batteries and solar power?

Unfortunately you will never save money generating your own power compared to purchasing it from a POCO.

it keeps me occupied and maybe one day if i learn enough might even give me an edge to get a job in the industry, its a hobby and like all hobbies you do it because you like to even if you poor im poor so i play with broken stuff, gives me something to do fixing it and then putting it all together. my whole systems so far iv spent less than

[SunEagle]

it keeps me occupied and maybe one day if i learn enough might even give me an edge to get a job in the industry, its a hobby and like all hobbies you do it because you like to even if you poor im poor so i play with broken stuff, gives me something to do fixing it and then putting it all together. my whole systems so far iv spent less than

I understand the desire to want to experiment and learn. I just caution you to do it safely and wisely. People have gotten hurt trying to learn electrical circuits without understanding how dangerous they can be.

[jflorey2]

if i go to a scrap yard and buy a few old Lead acid car batteries would it be safe to use them with the cheap ebay PWM charge controllers, im not that fussed about life span and such its more just for a plaything until i get a MPPT charge controller and some proper leisure batteries

It will work, sort of.

also is there a way to get 2 different AH batteries to hook up together to 24v? or is it just generally a bad idea

It is a very bad idea. The only way to make that work is to charge them individually and then monitor them individually, then shut down the inverter when any one battery goes below about 11.8 volts.

[vm1990]

thanks, ill probably end up getting a MPPT unit at some point so that i can use a 12v or 24v system and still get the best out of the panels, only reason i asked was to see if there was a way to get more out of the 30v panels without investing a chuck of money in expensive gear. i know PWM units just restrict voltage and give you the amps and a good MPPT will play with voltage to give watt for watt power, think ill get one in the end just take a while to save up the EPsolar MPPT

http://www.ebay.co.uk/itm/like/EPsolar-MPPT-Solar-Charge-Controller-Battery-Regulator-Max100V-Input-12V-24V-PK/192060940575?hlpht=true&ops=true&viphx=1&_trksid=p5197.c100068.m2280&_trkparms=ao%3D1%26asc%3D20140211130857%26meid%3De5c15d26a4ae4afa94f0885dd8aac6c1%26pid%3D100068%26clkid%3D2890667341103249742&_qi=RTM2063723

what would be best, i have 3 panels working @ 32v but diffrent Amps
32v 6A
32v 4A
32v 2A

am i right in thinking id be able to do 2 options? either
96v @ 4A or
32v @12A

if im missing something let me know im still learning and some of the explanations can be a bit confusing XD

[Mike90250]

panels in parallel, with separate fuses on each, according to the spec on each panel
32V 12A works
96V would be choked back to 2A by the small series panel

[vm1990]

Thanks for the advice I always confuse myself with currents and voltages I think I get an answer then start to over think it XD